1. Field of the Invention
The present invention relates to an image capture apparatus which has a function designed to correct a blur from a captured image caused by a camera shake or the like.
2. Description of the Related Art
With the recent downsizing of image capture apparatuses and the increase in the magnification of the optical system, a shake applied to the image capture apparatus or the like has become a major cause of degradation of the captured image. By focusing attention on this, there has been various image capture apparatuses with an image blur correction function for correcting a blur of captured image caused by a shake of the apparatus or the like.
Japanese Patent No. 4419466 discloses an image capture apparatus which includes an angular velocity sensor and corrects the blur of captured image by moving a shake-correction lens to cancel the output from the angular velocity sensor. The angular velocity sensor has a given output value (reference value) when no vibration is applied. To obtain a pure angular velocity applied to the image capture apparatus, the reference value needs to be subtracted from an output from the angular velocity sensor. However, this reference value fluctuates depending on the environment such as the temperature, so it is hard to accurately obtain the reference value. Japanese Patent No. 4419466 discloses a method for calculating the reference value more accurately.
However, the conventional technique disclosed in Japanese Patent No. 4419466 has the following problems. When the user performs a panning operation to change the shooting direction of the image capture apparatus, correcting even the motion component of the panning operation obstructs the panning operation of the user. In general, therefore, control to weaken the shake correction effect is performed at the time of panning. At this time, the result of the motion vector detection is given by the sum of the shake remaining component, which arises from an error of the above-mentioned reference value, and an image motion component, which arises from the weakening of the shake correction effect at the time of panning. The motion vector detection result at the time of panning does not indicate only the shake remaining component that arises from an error of the reference value, and no accurate reference value can be calculated.